Cellular telephones can have several modes of operation with differing levels of functionality. In an active mode, all the keys may be used, the display screen is active, and the user may use the telephone to speak with another person. In standby mode, the display screen is inactive to save power and lengthen the life of the batteries, but the cellular telephone may easily be switched to an active mode by depressing any of the buttons. Finally, some cellular telephones include a locked mode. In this mode, none of the keys are active and the user is required to depress a predetermined sequence of keys, often including a password, to switch the cellular telephone to the active mode.
Because of the hassle of switching a cellular telephone from the locked mode to the active mode, and vice versa, many users leave their cellular telephones in the standby mode while it is not in use. Because most keys are still functional while in standby mode, a cellular telephone being carried in a purse or in a carrier on a belt may inadvertently be placed into contact with something that can depress one or more of its keys. This is problematic in that the cellular telephone is switched to its active state, increasing the drain on the batteries. Further, in some cellular telephone models, a function may be activated by the depressing of a key, such as a speed dial function. Thus, with the depressing of a single key, a long distance telephone call can be made. Obviously, this may be expensive and needlessly waste valuable minutes from a user's calling plan.
To protect against this problem, several cellular telephones offer the locked mode. In a first example, to lock and unlock the keypad, the user may press the “function” key, then press the “*” key. In a second example, to lock the keypad, when “menu” is displayed in the option area of the display, the user must press the “mail” key three times to enable the key lock. To disable the lock mode, the user must press the “mail” key twice while “Free” is displayed in the option area of the display. In a third example, to lock the keys, the user must press Menu +9, or Menu +*. Thus, it is desireable to have a way of protecting against unwanted calls without the hassle of locking and unlocking the keypad.
There is further the problem of receiving phone calls while the cellular telephone is in the locked mode. In most examples, to receive a phone call, the user simply answers the call as if the cellular telephone was in standby mode. However, upon termination of the call, the cellular telephone immediately reverts to the locked mode. After receiving a phone call, it is not unusual for a user to desire to make another phone call based on the discussion he or she just had. Since the cellular telephone is in the locked mode, the user must go through the steps to switch the phone to active mode. It would therefore be desireable to provide a cellular telephone that, upon termination of a call in the locked mode, gives the user the option of choosing the mode in which to place the phone.
While the disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the disclosure to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and the equivalents falling within the spirit and scope of the invention as defined by the appended claims.